/*
 * Copyright (c) 2016 Chelsio Communications, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/tcp.h>
#include <linux/ipv6.h>
#include <net/inet_ecn.h>
#include <net/route.h>
#include <net/ip6_route.h>

#include "libcxgb_cm.h"

void
cxgb_get_4tuple(struct cpl_pass_accept_req *req, enum chip_type type,
                int *iptype, __u8 *local_ip, __u8 *peer_ip,
                __be16 *local_port, __be16 *peer_port)
{
        int eth_len = (CHELSIO_CHIP_VERSION(type) <= CHELSIO_T5) ?
                      ETH_HDR_LEN_G(be32_to_cpu(req->hdr_len)) :
                      T6_ETH_HDR_LEN_G(be32_to_cpu(req->hdr_len));
        int ip_len = (CHELSIO_CHIP_VERSION(type) <= CHELSIO_T5) ?
                     IP_HDR_LEN_G(be32_to_cpu(req->hdr_len)) :
                     T6_IP_HDR_LEN_G(be32_to_cpu(req->hdr_len));
        struct iphdr *ip = (struct iphdr *)((u8 *)(req + 1) + eth_len);
        struct ipv6hdr *ip6 = (struct ipv6hdr *)((u8 *)(req + 1) + eth_len);
        struct tcphdr *tcp = (struct tcphdr *)
                             ((u8 *)(req + 1) + eth_len + ip_len);

        if (ip->version == 4) {
                pr_debug("%s saddr 0x%x daddr 0x%x sport %u dport %u\n",
                         __func__, ntohl(ip->saddr), ntohl(ip->daddr),
                         ntohs(tcp->source), ntohs(tcp->dest));
                *iptype = 4;
                memcpy(peer_ip, &ip->saddr, 4);
                memcpy(local_ip, &ip->daddr, 4);
        } else {
                pr_debug("%s saddr %pI6 daddr %pI6 sport %u dport %u\n",
                         __func__, ip6->saddr.s6_addr, ip6->daddr.s6_addr,
                         ntohs(tcp->source), ntohs(tcp->dest));
                *iptype = 6;
                memcpy(peer_ip, ip6->saddr.s6_addr, 16);
                memcpy(local_ip, ip6->daddr.s6_addr, 16);
        }
        *peer_port = tcp->source;
        *local_port = tcp->dest;
}
EXPORT_SYMBOL(cxgb_get_4tuple);

static bool
cxgb_our_interface(struct cxgb4_lld_info *lldi,
                   struct net_device *(*get_real_dev)(struct net_device *),
                   struct net_device *egress_dev)
{
        int i;

        egress_dev = get_real_dev(egress_dev);
        for (i = 0; i < lldi->nports; i++)
                if (lldi->ports[i] == egress_dev)
                        return true;
        return false;
}

struct dst_entry *
cxgb_find_route(struct cxgb4_lld_info *lldi,
                struct net_device *(*get_real_dev)(struct net_device *),
                __be32 local_ip, __be32 peer_ip, __be16 local_port,
                __be16 peer_port, u8 tos)
{
        struct rtable *rt;
        struct flowi4 fl4;
        struct neighbour *n;

        rt = ip_route_output_ports(&init_net, &fl4, NULL, peer_ip, local_ip,
                                   peer_port, local_port, IPPROTO_TCP,
                                   tos & ~INET_ECN_MASK, 0);
        if (IS_ERR(rt))
                return NULL;
        n = dst_neigh_lookup(&rt->dst, &peer_ip);
        if (!n)
                return NULL;
        if (!cxgb_our_interface(lldi, get_real_dev, n->dev) &&
            !(n->dev->flags & IFF_LOOPBACK)) {
                neigh_release(n);
                dst_release(&rt->dst);
                return NULL;
        }
        neigh_release(n);
        return &rt->dst;
}
EXPORT_SYMBOL(cxgb_find_route);

struct dst_entry *
cxgb_find_route6(struct cxgb4_lld_info *lldi,
                 struct net_device *(*get_real_dev)(struct net_device *),
                 __u8 *local_ip, __u8 *peer_ip, __be16 local_port,
                 __be16 peer_port, u8 tos, __u32 sin6_scope_id)
{
        struct dst_entry *dst = NULL;

        if (IS_ENABLED(CONFIG_IPV6)) {
                struct flowi6 fl6;

                memset(&fl6, 0, sizeof(fl6));
                memcpy(&fl6.daddr, peer_ip, 16);
                memcpy(&fl6.saddr, local_ip, 16);
                if (ipv6_addr_type(&fl6.daddr) & IPV6_ADDR_LINKLOCAL)
                        fl6.flowi6_oif = sin6_scope_id;
                dst = ip6_route_output(&init_net, NULL, &fl6);
                if (dst->error ||
                    (!cxgb_our_interface(lldi, get_real_dev,
                                         ip6_dst_idev(dst)->dev) &&
                     !(ip6_dst_idev(dst)->dev->flags & IFF_LOOPBACK))) {
                        dst_release(dst);
                        return NULL;
                }
        }

        return dst;
}
EXPORT_SYMBOL(cxgb_find_route6);